scholarly journals In vivo monitoring of microneedle-based transdermal drug delivery of insulin

2018 ◽  
Vol 11 (05) ◽  
pp. 1850032 ◽  
Author(s):  
Jiawei Zhao ◽  
Yongbo Wu ◽  
Junbo Chen ◽  
Bangrong Lu ◽  
Honglian Xiong ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Polyvinyl Alcohol ◽  
Functional Imaging ◽  
Transdermal Drug Delivery ◽  
Mouse Skin ◽  
Laser Speckle ◽  
Structural Imaging ◽  
Contrast Imaging ◽  
Functional Changes

Soluble microneedles (MNs) have recently become an efficient and minimally invasive tool in transdermal drug delivery because of their excellent biocompatibility and rapid dissolution. However, direct monitoring of structural and functional changes of MNs in vivo to estimate the efficiency of insulin delivery is difficult. We monitored the dissolution of MNs to obtain structural imaging of MNs’ changes by using optical coherence tomography (OCT). We also observed the effect of MNs on microvascular conditions with laser speckle contrast imaging (LSCI) and measured the blood perfusion of skin to obtain functional imaging of MNs. We determined the performance of two soluble MN arrays made from polyvinyl alcohol (PVA) and polyvinyl alcohol/polyvinylpyrolidone (PVA/PVP) by calculating the cross-sectional areas of the microchannels in mouse skin as a function of time. Moreover, the change in blood glucose before and after using MNs loaded with insulin was evaluated as an auxiliary means to demonstrate the ability of the soluble MNs to deliver insulin. Results showed that the structural imaging of these MNs could be observed in vivo via OCT in real time and the functional imaging of MNs could be showed using LSCI. OCT and LSCI are potential tools in monitoring MNs structural and functional changes.

Laser Speckle Contrast Imaging on in vivo Blood Flow: a Review

2018 ◽  
Vol 45 (2) ◽  
pp. 0207006
Author(s):  
李晨曦 Li Chenxi ◽  
陈文亮 Chen Wenliang ◽  
蒋景英 Jiang Jingying ◽  
范颖 Fan Ying ◽  
杨婧孜 Yang Jingzi ◽  
...  
Keyword(s):  
Blood Flow ◽  
Laser Speckle ◽  
Contrast Imaging ◽  
Laser Speckle Contrast Imaging ◽  
Speckle Contrast

FA05.03: EFFECT OF EPHEDRINE ON GASTRIC CONDUIT PERFUSION MEASURED BY LASER SPECKLE CONTRAST IMAGING (LSCO) AFTER ESOPHAGECTOMY: A PROSPECTIVE IN-VIVO COHORT STUDY

2018 ◽  
Vol 31 (Supplement_1) ◽  
pp. 10-10
Author(s):  
Sanne Jansen ◽  
Daniel De Bruin ◽  
Simon Strackee ◽  
Mark I Van Berge Henegouwen ◽  
Ton Van Leeuwen ◽  
...  
Keyword(s):  
Anastomotic Leakage ◽  
Gastric Tube ◽  
Gastric Conduit ◽  
Laser Speckle ◽  
Contrast Imaging ◽  
Laser Speckle Contrast Imaging ◽  
Speckle Contrast ◽  
Before And After ◽  
Gastric Tube Reconstruction

Abstract Background Compromised perfusion due to ligation of arteries and veins in esophagectomy with gastric tube reconstruction often (5–20%) results in necrosis and anastomotic leakage, which relate to high morbidity and mortality (3–4%). Ephedrine is used widely in anesthesia to treat intra-operative hypotension and may improve perfusion by the increase of cardiac output (CO) and mean arterial pressure (MAP). This study tests the effect of ephedrine on perfusion of the future anastomotic site of the gastric conduit, measured by Laser Speckle Contrast Imaging (LSCI). Methods This prospective, observational, in-vivo pilot study includes 26 patients undergoing esophagectomy with gastric tube reconstruction from October 2015 to June 2016 in the Academic Medical Center (Amsterdam). Perfusion of the gastric conduit was measured with LSCI directly after reconstruction and after an increase of MAP by ephedrine 5 mg. Perfusion was quantified in flux (LSPU) in four perfusion locations, from good perfusion (base of the gastric tube) towards decreased perfusion (fundus). Intra-patient differences before and after ephedrine in terms flux were statistically tested for significance with a paired t-test. Results LSCI was feasible to image gastric microcirculation in all patients. Flux (LSPU) was significantly higher in the base of the gastric tube (791 ± 442) compared to the fundus (328 ± 187) (P < 0.001). After administration of ephedrine, flux increased significantly in the fundus (P < 0·05) measured intra-patients. Three patients developed anastomotic leakage. In these patients, the difference between measured flux in the fundus compared to the base of the gastric tube was high. Conclusion This study presents the effect of ephedrine on perfusion of the gastric tissue measured with LSCI in terms of flux (LSPU) after esophagectomy with gastric tube reconstruction. We show a small but significant difference between flux measured before and after administration of ephedrine in the future anastomotic tissue (313 ± 178 vs. 397 ± 290). We also show a significant decrease of flux towards the fundus. Disclosure All authors have declared no conflicts of interest.

Polyvinyl Alcohol/Hydroxyethylcellulose Containing Ethosomes as a Scaffold for Transdermal Drug Delivery Applications

2020 ◽  
Vol 191 (4) ◽  
pp. 1624-1637
Author(s):  
Gomaa El Fawal ◽  
Huoyan Hong ◽  
Xinran Song ◽  
Jinglei Wu ◽  
Meiqi Sun ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Polyvinyl Alcohol ◽  
Transdermal Drug Delivery ◽  
Drug Delivery Applications

scholarly journals A Robust Method for Adjustment of Laser Speckle Contrast Imaging during Transcranial Mouse Brain Visualization

Photonics ◽  
2019 ◽  
Vol 6 (3) ◽  
pp. 80 ◽  
Author(s):  
Vyacheslav Kalchenko ◽  
Anton Sdobnov ◽  
Igor Meglinski ◽  
Yuri Kuznetsov ◽  
Guillaume Molodij ◽  
...  
Keyword(s):  
Biological Tissues ◽  
Laser Speckle ◽  
Robust Method ◽  
Scattering Media ◽  
Contrast Imaging ◽  
Speckle Contrast ◽  
Non Invasive ◽  
Sagittal Sinus ◽  
Brain Vasculature

Laser speckle imaging (LSI) is a well-known and useful approach for the non-invasive visualization of flows and microcirculation localized in turbid scattering media, including biological tissues (such as brain vasculature, skin capillaries etc.). Despite an extensive use of LSI for brain imaging, the LSI technique has several critical limitations. One of them is associated with inability to resolve a functionality of vessels. This limitation also leads to the systematic error in the quantitative interpretation of values of speckle contrast obtained for different vessel types, such as sagittal sinus, arteries, and veins. Here, utilizing a combined use of LSI and fluorescent intravital microscopy (FIM), we present a simple and robust method to overcome the limitations mentioned above for the LSI approach. The proposed technique provides more relevant, abundant, and valuable information regarding perfusion rate ration between different types of vessels that makes this method highly useful for in vivo brain surgical operations.

scholarly journals Improved Biosafety and Transdermal Delivery of Aconitine via Diethylene Glycol Monoethyl Ether-Mediated Microemulsion Assisted with Microneedles

Pharmaceutics ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 163 ◽  
Author(s):  
Yongtai Zhang ◽  
Hongmei Hu ◽  
Qian Jing ◽  
Zhi Wang ◽  
Zehui He ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Diethylene Glycol ◽  
Transdermal Drug Delivery ◽  
Skin Irritation ◽  
In Vivo Microdialysis ◽  
Monoethyl Ether ◽  
Glycol Monoethyl Ether ◽  
Diethylene Glycol Monoethyl Ether

In the current study, diethylene glycol monoethyl ether-mediated microemulsions were combined with microneedles for enhanced transdermal aconitine delivery. The oil-in-water microemulsion increasedaconitine solubility and enhanced transdermal drug delivery and assistance with metal microneedles enhanced permeation of the aconitine-loaded microemulsion. Carried by the microemulsion, the in vitro permeability of aconitine was significantly enhanced, and further improved using microneedles. In vivo microdialysis revealed that the subcutaneous local drug concentration reached a high level within 30 min and remained relatively consistent to the end of the experimental period. AUC0-t of the microemulsion group was significantly higher than that of the aqueous solution group, and the microemulsion combined with microneedles group achieved the highest AUC0-t among the tested groups. The microemulsion and microdialysis probe also showed good biocompatibility with skin tissue. The microemulsion could be internalized by HaCaT and CCC-ESF-1 cells via lysosomes. The in vitro cytotoxicity of aconitine toward skin cells was reduced via encapsulation by microemulsion, and the prepared microemulsion developed no skin irritation. Hence, transdermal aconitine delivery and drug biosafety were effectively improved by loading into the microemulsion and assisting with microneedles, and in vivo microdialysis technique is suitable for realtime monitoring of transdermal drug delivery with microemulsion-based drug vehicles.

scholarly journals A new simulation method for laser speckle imaging to investigate hemodynamics

2019 ◽  
Vol 128 ◽  
pp. 02001
Author(s):  
X Sang ◽  
D Li ◽  
B Chen
Keyword(s):  
Speckle Pattern ◽  
Simulation Method ◽  
Laser Speckle ◽  
Contrast Imaging ◽  
Laser Speckle Imaging ◽  
Speckle Imaging ◽  
Dynamic Speckle ◽  
Speckle Size ◽  
The One

Speckle simulation is a powerful protocol to investigate the properties of speckle and evaluate image processing method. However, only static speckle images can be simulated by available methods without considering time-integrated effect of CCD. A time–integrated dynamic speckle simulation method basedon coherent imaging was developed. Through the new simulation method, the effect of speckle size on LSCI was investigated. The smaller the speckle size is, the higher the spatial resolution become.But the one-dimensional speckle size should exceed two pixels to sample the speckle pattern. The characteristics of existing speckle contrast imaging methods were studied based on spatial statistics, and optimal parameters are given to obtain accurate and less noisy image. In general, the new simulation method for laser speckle imaging is a powerful tool to monitor blood flow in vivo and lay a solid foundation for the study of hemodynamics.

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